Full Revolution issues - Rotary Axis - Barrel Organ Machine

Hello,

I'm working on a special machine to cut cardboard for barrel organ (my parents are making these french musical instruments). It's a 3 axis machine and im using the MX3660 driver with Linux cnc 2.7. Here the beta version of the machine on my website : antoninodin.com/CARDBOARD-MACHINE ) .

I have an issue with the rotary axis A, I dont manage to do a full revolution in both direction : when I do a G91 G0 A360 it's OK but when I do a G91 G0 A-360 there is an offset ( I have marked my physicial axis to see it). I have tried to change the settings all the day but I dont underrstand why I dont have a full revolution in both directions...

Here the settings of the A axis in the Ini files :



Thanks a lot for your help.

thanks !

here the HAL and INI files :




The offset seems to be always the same. here :

a video that shows the offset of this axis :
I do 2 times G91 G0 A360 and then 2 times G91 G0 A-360.

For the G90 i have an error : " absolute position invalid for the wrapped rotary axis A"

I dont think that the problem is coming from a mechanical backlash.
I have tried without the Wrapped_Rotary and it's not changing anything.

What is weird is that I can send G91 G0 A360 many times and I will never have any offset, but when It's a G91 G0 A-360, it's seems that the motor is doing less steps that needed... By testing, i figured it out that a G91 G0 A-364.4 is actually doing a full revolution, but i dont understand why ?

I was expecting that a A360 and a A-360 will do a full revolution and having both at the exact same position...

thanks for your help!

So from the mark (the origin) I have jogged the axis to -360°, and it came back to the mark correclty (so 1 revolution). But then the G91 G0 A360 do an offset. We can also notice that after these two moves, I can come back to the mark at 0.00 by doing again -360°. But, If I jog the axis to A360°, it still getting an offset. I have to reset the origin of the axis, to do be able to do A360° and do a full revolution.

So to sum up, once the origin is defined, If the first jog is negative (-360°), the positive jog (+360) will be offset. In the contrary, if the first jog is positive, it's the negative jog that will be offset.

The offset is always the same whatever is 1 or 4 revolutions.

it seams to be a SCALE and Homing issue
WHAT is the MICROSTEPPING of the MX3660 set
and what is the Drive system Timingbelt 5:1 ?

The microstepping is set to 1600 on the MX3660. So 8 in the StepConf wizzard Microstepping.

bbsr_5a wrote:

what is the Drive system Timingbelt 5:1 ?

I'm not sure about what you mean about "Drive system Timigbelt 5:1", as the picture posted below, this axis is a direct drive, and there is no timigbelt.

I have tried to change the microstepping and the scale, but i had still some offset...